Transmission mechanism



June 8, 1943. A, w. PLENSLER 2,321,317

TRANSMIS S ION MECHANI SM Filed May 17, 1941 0%201 /2/01' Q/fIQ/Z (1 %/%/2J/ Patented June 8, 1943 TRANSMISSION MECHANISM Alexander W. Plensler, Chicago, Ill., assignor to Belmont Radio Corporation, Chicago, 11]., a corporation of Illinois Application May 17, 1941, Serial No. 393,901

2 Claims.

This invention relates in general to control apparatus and more in particular to transmission mechanism in a radio tuning system of inductance type for connecting linearly adjustable tuning elements in driven engagement with a rotary control member.

It is an object of this invention to provide an improved control system for controllable appa-' ratus, and particularly an improved tuning syspendently .of any rotation of the IQtary control member.

Yet another object of this invention is to provide in an inductance tuning system for a radio receiver having a plurality of coil units with core elements linearly movable therein to tuning positions by a rotary control member, improved transmission means for connecting said elements and control member which permits individual adjustment of each element relative to its corresponding coil and operates during all times of tuning operation to simultaneously move all of the tuning elements while retaining their adjusted relative positions. v

A still further object of this invention is to provide improved transmission means for connecting a rotary control member in driving engagement with a plurality of linearly movable adjustable units arranged at substantially right angles there- 4 to and spaced axially thereof, wherein the driving connection retains the adjustable units fixed in their positions axially of the control member.

A feature of this invention is found in the provision of means for operatively connecting a rotary driving member with a plurality of linearly movable longitudinally spaced adjustable elements having threaded adjustment portions arranged substantially at right angles to the driving member, in which the driving member is provided with axially spaced peripherally extending threaded portions adapted for meshing engagement with the element adjustment portions, the peripheral threaded portions being of a substanti'aily concave curvature so as to retain the ad-.

justment portions in fixed positions axially of the driving member.

Yet another feature of this invention is found in the provision of means for connecting a rotary driving member with a plurality of linearly movable longitudinally spaced adjustable elements having threaded adjustment portions arranged at substantially right angles to the driving member in which the driving member is provided with axially spaced threaded portions for receiving the element adjustment portions in meshed engagement, with the meshed engagement being re tained by means yleldably movable laterally of the control member and adapted to permit the adjustable elements being separately disengaged from the driving member, and when in meshed engagement permitting individual rotation of the elements relative to the driving member.

Further objects, features, and advantages of this invention will become apparent from the lollowing description when taken in connection with the accompanying drawing in which:

Fig. l is a plan view showing a complete assembly of the invention;

Fig. 2 is a side view as in Fig. 1;

Fig. 3 is a fragmentary sectional view taken on seen along the line 2-! line 3-3 in Fig. 1 showing the meshed engagement of an adjustable tuning element with the rotary control member;

Fig. 4 is a fragmentary sectional view taken along the line ll in Fig. 1 showing the meshed engagement of an adjustable tuning element with the rotary control member at a position removed 90 degrees from the section of Fig. 3; and

Fig. 5 is a fragmentary sectional view as seen along the line 5-5 in Fig. 2 showing the means for mounting a coil inian inductance unit.

The invention is illustrated with a radio tuning system having a plurality of longitudinally spaced inductance units, with each of the units including a coil with an adjustable core element linearly movable therein. Each adjustable element is connected at one end to a connector member, the free end of the connector being threaded and positioned for engagement with one side of a rotary control member, all of the connectors being arranged substantially normal to the control member. The control member is of round shape and is provided on the periphery thereof with axially spaced threaded portions corresponding to the threaded ends of the connectors. The threaded portions on the control member are of a substantially concave curvature to fully receive in meshed engagement the threaded connec'tor ends, this meshed engagement being retained by means frictionally engaging a connector and yleldably supporting it against the control member. Individual adjustment of an adjustable element is accomplished by rotating its corresponding connector while the control member is stationary, with rotation 'of the control member during a normal tuning operation serving to linearly and simultaneously move all of the adjustable elements.

With reference to the drawing, there is shown in Fig. 1 a radio tuning system of inductance type having a plurality of inductance units l0, each of which includes a coil ll (Fig. 5) with an adjustable core element or metal slug l2 linearly slidable therein. The inductance units iii are illustrated as being held together in longitudinal alignment by a. strap member l8, and mounted at their back sides 28 to one leg of a right-angled supporting bracket H, the other leg of which is supported on and suitably secured to a base or frame member l6.

Referring to Fig. 5, the assembly of the coil H and metal slug l2 in each inductance unit, is seen to include'an insulating sleeve l1 having one end extending through an enlarged opening l8 formed in the front side 28 of the casing or can of an inductance unit In and yieldingly mounted at its other end by means of an eyelet 2i extending through an aperture in such other end, and through a rubber grommet 22 carried in a corresponding aperture in the insulating plate or back side 28 of the inductance unit. In order to provide an exceptionally positive mounting for the sleeve l1, a. one-half eyelet 24 with an enlarged outer bearing surface is employed intermediate the eyelet 2| and th grommet 22.

This mounting for th sleeve provides for its pivotal movement relative to the insulating plate 28 to follow the movement of the driven slug 2,11 in fact such movement is necessary, so that there will be no binding between the slug and sleeve as will be later fully expained.

Each slug. or adjustable core element I2 is connected at the end thereof which projects from the sleeve l1 to one end of a connector or.rod member 26, so that the member 26 extends axially outwardly from the core element. The opposite end of each rod or link member 26 is provided with a threaded adjustment portion 21, which extends transversely of and'is positioned adjacent to one side of a rotary control or driving member 28 for engagement therewith.

As is clearly apparent from Figs. 1 and 2, the rod members 26, by virtue of their extending axially outwardly from the core elements l2, are longitudinally arranged in a spaced relation and lie substantially in a common plane. The control shaft 28 is positioned substantially normal to the rod members 26 and is rotatably supported tions 21.

in bearing or journal members 28 which are mounted upon and suitably secured to the frame base l6. Axial movement of the control shaft 28 in the bearing members 28 is completely eliminated in an obvious manner by adjustable thrust 82 for meshing engagement therewith.

collars 8i, which are mounted on the shaft and to the outside of each bearing portion.

A driving connection between each connector 26 and the control shaft 28 is accomplished by the provision-of peripherally extending threaded portions 82 provided on the shaft 28 and corresponding to the threads on the adjustment por- The threaded peripheral portions 82 are spaced axially of the control shaft 28 a distance corresponding to the longitudinal spacing of the connectors 26. Thus with the connectors 28 arranged at right angles to the control shaft 28 and to one side thereof, each adjustment por- As shown particularly in Fig. 3 each peripheral threaded portion 82 on the shaft 28 is seen to be of a substantially concave curvature to form an annular threaded recess. On positioning of an adustment portion 21 in meshed engagement with a threaded portion 82, therefore, the adjustment portion is seated within the threaded recess 82 so as to be retained in a fixed position axially of the shaft 28. A self-aligned positioning of each connector 26 axially of the control shaft 28 and at substantially right angles thereto is thus obtained concurrently upon its operative engagement with the shaft. This operative engagement of the connectors 26 and shaft 28 is retained by a spring member 88 corresponding in number to the connectors. Each spring 88 is supported at one end on the base member l6, and is under an initial tension such that its opposite end 86- frictionally engages a corresponding adjustment portion 21 to 'yieldably support the portion 21 against the control shaft 28.

In the operation of the tuning system, it is desirable that each core element l2 be adapted for individual adjustment to a position relative to the other core elements in the tuning system. This is accomplished-in the present invention by simply rotating the connector member 26 corresponding to the element l2 which is being adjusted. By virtue of the meshed engagement of the connector 26 with the control shaft 28 this rotation provides for a linear movement of the core element under adjustment'independently of any rotation of the control shaft 28 or linear movement of any of the remaining core elements. Since each adjustment portion is threadably engageable with the shaft 28 over its entire periphery it is clearly apparent that a very fine adjustment can be obtained in this manner. After the core elements l2 have been thus adjusted to their relative tuning positions, this relative position is retained during subsequent tuning operations by the positive meshed engagement (Figs. 3 and 4) of each connector member 26 with the control shaft 28. On rotation of the ment thereof relative to the element l2. Because of this flexible mounting, any inaccuracies in the alignment of the connector 26 relative to the elements l2 and control shaft 28, or arising, from any possible variations in the diameters of the threaded portions 21 and peripheral threaded portions 32 are readily compensated for without in any way binding the elements l2 in the sleeves. Also, in the event an element or slug l2 should become injured to such an extent that it. no longer. operates satisfactorily, sufiicient movement or play is provided by the sleeve' to permit the connector being disengaged and moved away from the shaft 28 so that the element i2 can be withdrawn completely from its corresponding sleeve [1. Since each spring 88 is yieldable laterally of the shaft 28 the disengagement of a connector and tlie shaft is simply accomplished.

by merely moving the spring end 3i away from the adjustment portion 21.

From a consideration of the foregoing description and the drawing, the-invention is seen to provide a transmission mechanism connecting a rotary control member to simultaneously drive a plurality of linearly movable adjustable elements, which is .of simple and rugged construction and which provides for a quick and easy individual adjustment of the elements while retaining such adjustments during normal tuning operations.

Although the invention has been described with reference to a specific embodiment thereof, it is to be understood that it is not to be so limited since alterations and modifications therein can be made which are within the full intended scope of the invention as defined by the appended claims.

I claim:

1. In control means having a rotary control member for driving a linearly movable adjustable element, the means for operatively connecting said element with said rotary control member including a threaded portion on said adjustable element extending longitudinally thereof and transversely of said control member, said control member being of straight form over substantially its complete length and having an annular recess therein within its peripheral confines, with the walls of said recess having threads thereon corresponding to said threaded portion, and said recess having a contour corresponding to the periphery of said threaded portion, and means acting on said threaded portion yieldably urging the same into meshing engagement with said control member at said recess, with the walls of said recess retaining said threaded portion against movement axially of said control member.

2. In control means having a rotary control member for simultaneously driving a plurality of linearly movable adjustable elements spaced axially of said control member, means for connecting said control member and adjustable elements including a rotatable connector member for each of said elements extended normal to said control member, with each connector member being connected at one end to a corresponding element and having a threaded adjustment portion at its opposite end adjacent one side of said control member, said control member being of straight form over its length and having a plurality of axially spaced annular recesses-on the periphery thereof corresponding to said adjustable elements, with each of said recesses being of a concave form and having threads on the walls thereof for meshing engagement with a corresponding threaded adjustment portion, and means yieldably supporting said adjustment portions in meshing engagement with said control member at a corresponding recess, with the walls of a recess acting to retain a corresponding threaded portion against movement axially of the control member, with rotation of a. connector member, while said rotary control member is stationary, providing for the separate adjustment of an adjustable element, and rotation of said control member linearly moving all of said adjustable elements simultaneously and in the same direction.

ALEXANDER. W. PLENSLER. 

